Electrosynthesis of 2-Alkyl-4(3H)-quinazolinones

Abstract

Electroreduction of 2-nitrobenzonitrile in a variety of alcohols leads to 2-alkyl-4(3 H)-quinazolinones via incorporation of the alkyl chain of the alcohols under cyclization. Physical properties and spectroscopic data of the quinazolinones and a probable pathway of their formation are given.

Recent Advances in the Electrochemical Reduction of Substrates Involving N−O Bonds

“…2‐Nitrobenzonitriles (Scheme , 17a ) have been converted to 3 H ‐2‐alkyl‐4‐quinazolinones ( 17b ) using a mercury pool cathode and carbon anode in an undivided cell under potentiostatic control . In the reaction, an alcoholic solvent is oxidized at the anode to an aldehyde that eventually reacts with a hydroxylamine intermediate that is produced at the cathode from the reduction of 2‐nitrobenzonitrile.…”

The preparation and applications of amides using electrosynthesis

“…27 Scheme 9 Electrochemical quinazolinone synthesis and scope. 28,29 did not undergo the desired Favorskii rearrangement (though did still produce amide products). 30 The mechanism for this reaction is shown in Scheme 12, starting with iodide oxidation to produce I 2 , which reacts with 18 to form an α-iodoketone 19.…”

“…These conditions were tolerated by a range of functional groups to give reasonably good yields. 27 There are also examples of amide bonds being formed from nitrile groups other than in MeCN, such as the work of Estrada and Rieker from 1994, 28,29 which showed how 2-nitrobenzonitrile 14 could be converted into quinazolinones 15 in the presence of various alcohols. This reaction employed a mercury pool cathode and a carbon anode in an undivided cell and is shown in Scheme 9.…”

“…Most examples tested gave moderate to good yields, however, some exceptions include dibenzyl ketones bearing electron-donating substituents (such as OMe), as these Scheme 10 Proposed mechanism for electrochemical quinazolinone synthesis. 28,29 Scheme 7 Electrochemical iodide oxidation and reaction with MeCN. 26 Scheme 8 Anodic flow oxidation in the presence of MeCN and H 2 O to produce amides.…”

Dual Roles of Supporting Electrolytes in Organic Electrosynthesis

“…Different alcohols serve as solvents, which were implemented in the resulting 2-alkyl-4(3H)-quinazolinone 50 products. [43] Intramolecular reactions are shown in Schemes 11c and 11d. In a protocol presented by Waldvogel et al nitrobenzamide substrates 51 are reduced to the corresponding hydroxylamine intermediates 48 using sulfuric acid as a supporting electrolyte (Scheme 11c).…”